Hmm. Sounds fun.

I'd complain to Conforama. I wouldn't let it go, given the facts you've given so far...

BUT, if I wanted to get rid of a bed the easiest way in Basel is to take it to the dump at Birsfelden. They weigh your car on arrival and on departure. A helpful chap aids you in unloading and gives you a chitty for the type of junk (e.g. if it is an electronic device - nothing to pay ). You pay according to weight, and if it is chargabel, then it seems there's a minimum charge of about 6 CHF. But that covers 20Kg of burnable rubbish.

Maybe there is one near Zürich.